Method for drawing wire for staples

ABSTRACT

There is a method for the production of stapling wire for use in the graphic industry for stapling periodicals, brochures and the like. A drawable wire is drawn from an initial material (A) having a low carbon content which is drawn in a first drawing step from a starting diameter (D 1 ) to a temporary diameter (D 2 ). This wire is drawn in a second drawing step from the temporary diameter (D 2 ) to a final diameter (D 3 ), so that a stapling wire results. This process provides a simple and economical method for producing stapling wire, wherein stapling wire is produced to fulfill the requirements of the graphic industry. In addition, this second drawing step is performed without previously subjecting the wire to a heat treatment.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a method for the production ofstapling wire for use in the graphic industry for stapling periodicals,brochures, and the like. The method involves drawing a wire from aninitial material in a first drawing step from an initial diameter to anintermediate diameter. The wire is redrawn in a second drawing step fromthe intermediate diameter to a final diameter, to form the staplingwire.

[0003] 2. The Prior Art

[0004] Methods of the type initially described are already known inpractice. In a known method, the starting material, which typically hasan initial diameter of approximately 5.5 mm, is drawn in a first drawingstep to an intermediate diameter of 2.2 mm. Subsequently, this wire isannealed, so that, after a subsequent galvanizing stage, it can be wetdrawn to the desired final dimension, which typically is in the rangefrom 0.3 to 0.7 mm.

[0005] While the galvanizing step immediately follows the annealing stepin the known method cited, in another method known from practice, thewire drawn to the intermediate diameter is coiled up after the firstdrawing step and heat-treated in the coiled state. Subsequently, thewire having the intermediate diameter is galvanized, with the wire beinguncoiled and recoiled after galvanizing, which is typically doneelectrolytically. These steps are followed by the step of wet drawing tothe final diameter.

[0006] The stapling wire produced based on this method is finally coiledafter the second drawing step and supplied to the graphic industry.Printers and similar operations are meant by the graphic industry, whouse the stapling wire to staple together periodicals, brochures, and thelike. For wire stitching and/or stapling of periodicals, the wire issuccessively pulled off and cut from the coil and/or the spool at theprinters. Subsequently, the cut wire pieces are bent so that individualstaples result, which are then stapled into the backs of individualperiodicals.

[0007] To staple periodicals at the printers rapidly and withoutproblems, the stapling wire must have very specific properties. Theseinclude the wire being relatively hard to penetrate the backs of theperiodicals without problems, but also being easily shapeable into astaple. In addition, the wire and/or the staples produced from it mustkeep their shape after the stapling method. For example, the wire mustnot unbend, which not only interferes with the stapling, but also canlead to injuries if a reader passes his hand over the point of a staple.Another essential requirement of the stapling wire is that it can be cutwell. It is important during cutting that no so-called flags form on thecut ends of the wire. These flags are pointed regions which project fromthe actual cut faces. These flags can lead to the stapling wire notpenetrating the backs of the booklets perpendicularly during stapling,but going in at an angle, so that correct stapling is not possible.

[0008] It is known from Hirschfeld, M.: Drahtziehen I. (Wire Drawing I.)in: Werkstatt 328, Carl Hanser Verlag, Munich, 1964 that the materialrequirements of the wire increase hyper-proportionally during wireproduction in large total reduction of the wire cross-section. To reducethese requirements, it is possible to reduce the cross-section inmultiple steps. However, this measure leads to an uneconomically highnumber of individual steps by larger total reduction. Thus, heattreatments before, during and after improve the formability of the workmaterial. The method engineering effort, however, also increases throughthis heat treatment. Moreover, heat treatments lead to additional costs.

SUMMARY OF THE INVENTION

[0009] One object of the present invention is to provide a method forthe production of stapling wire that can be performed simply andeconomically and with which a wire can be produced that fulfills therequirements placed by the graphic industry without any additional stepsrequired.

[0010] The previously indicated and derived object is achieved by usinga method of the type initially cited. Essentially the wire does notundergo any heat treatment during the drawing process from a startingdiameter to a final diameter. According to the invention, the productionof a stapling wire corresponding to the requirements in the graphicindustry, provides an improved wire with no heat treatments. Leaving outthe heat treatment reduces the production time of the wire and alsoreduces the production costs, because the heat treatment creates asignificant portion of the overall production costs.

[0011] There are numerous product advantages as well. Specifically, thestapling wire produced according to the method of the invention hasbetter properties for stapling periodicals and similar items than astapling wire produced from the same starting material according to amethod of the prior art. The stapling wire produced from the inventivemethod can, on one hand, be shaped very well, but, in addition, keepsits shape exceptionally well after stapling, so that unbending of thewire after stapling is not a concern.

[0012] In addition, the stapling wire according to the invention is veryhard, which is very important, particularly when stapling of thickperiodicals. Therefore, a thinner wire can be used, which is moreeconomical, than in the prior art. In addition, the stapling wire of theinvention can be cut very well so that no flags result. This can beclearly explained in that the wire produced according to the method canalmost be called brittle, so that a flat cut surface without flagsresults during the cutting of the wire.

[0013] The method according to the invention leads to very good resultsin wires in which the starting material has a relatively low carboncontent of less than 0.1 weight-percent, particularly less than 0.06weight-percent.

[0014] A starting material can be used which permits a reduction incross-section from the starting diameter to the final diameter of morethan 80%, preferably more than 99%. Depending on the diameter, areduction in diameter by a factor of up to 100 is possible. Typically, awire with a starting diameter of less than 10 mm is used as the startingmaterial. Currently, wires with a starting diameter of approximately 5.5mm are frequently used in practice.

[0015] The final diameter is to be less than 1 mm and is currentlybetween 0.7 and 0.3 mm in practice, depending on the requirements of theclient.

[0016] To protect the stapling wire from corrosion or to fulfillspecific requirements of the client, a metallic coating is applied as asurface finish to the stapling wire. In the method according to theinvention, this coating can be provided as an intermediate coatingbetween the first and second drawing steps. The intermediate coatingbefore the redrawing in the second drawing step leads to a stapling wireonto which the coating adheres particularly well when the staples areproduced from the stapling wire and then inserted in the periodicals,brochures, or the like. However it is also possible to apply the coatingas a final coating, such as after the second drawing step. However, thiscoating requires separate cleaning of the wire to ensure good adhesionof the coating to the wire.

[0017] Besides copper, nickel, or tin coatings, which are possible inprinciple in addition to other coatings, the wire should be galvanizedbetween the first and second drawing steps.

[0018] The first drawing step should be performed with the dry drawingprocess. In this drawing step, multiple drawing dies with smaller andsmaller diameters are typically used. The second drawing step can beperformed with wet drawing, or also with the dry drawing process. Incontrast to the dry drawing process, the wire is guided through a bathbefore and/or during drawing in the wet drawing process.

[0019] A dry lubricant is preferably used to lubricate the wire when thedrawing in the first drawing step. This lubricant, used in the firstdrawing step, should be cleaned off of the wire after the first drawingstep and before coating, to essentially completely remove the drylubricant. The surface cleaning could be performed with mechanicalcleaning.

[0020] However, the wire should be washed off using chemicals, such assolvents. In addition, the chemical cleaning should be combined with themechanical cleaning.

[0021] Although it is possible to perform the first and second drawingsteps in one single process step, the wire should be coiled up at leastonce between the first and second drawing step. The first and seconddrawing steps can be performed independently from one another so that itis not necessary to adjust the drawing speeds of the two drawing stepsto one another. However, it is also favorable from a manufacturingtechnology viewpoint to keep the two drawing steps separate from oneanother because, if one of the drawing steps breaks down, the other canbe operated without any further measures.

[0022] In addition, the first drawing step, the coating step, and thesecond drawing step, are process steps independent from one another,between each of which the wire is coiled up, to be able to ensure theindependence of the individual steps.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Other objects and features of the present invention will becomeapparent from the following detailed description considered inconnection with the accompanying drawings which disclose at least oneembodiment of the present invention. It should be understood, however,that the drawings are designed for the purpose of illustration only andnot as a definition of the limits of the invention.

[0024] In the drawings wherein similar reference characters denotesimilar elements throughout the several views:

[0025]FIG. 1 shows a schematic illustration of the method based on theprior art for the production of stapling wire,

[0026]FIG. 2 shows a schematic illustration of the method according tothe invention for the production of stapling wire;

[0027]FIG. 3 shows a schematic illustration of a further embodiment ofthe method according to the invention, and

[0028]FIG. 4 shows a stress-strain diagram from which the properties ofstapling wire of the prior art are compared to the stapling wireproduced from the method according to the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0029] Referring to the drawings, FIG. 1 shows the prior art process forthe production of stapling wire which is intended for use in the graphicindustry for stapling of periodicals and the like. A drawable wireserves as the starting material A, which possibly has been previouslymechanically and/or chemically descaled. Subsequently, the startingmaterial A is drawn in a first drawing stage B with multiple drawingdies to a smaller intermediate diameter. The drawn wire is then coiledup in stage C. Following this step, the wire is then annealed in stageD, i.e. subjected to a heat treatment. Immediately following this step,the wire is galvanized in stage E.

[0030] In another known method, not shown, steps D and E can also beseparate steps, between which the wire is again coiled up.

[0031] Following step E the wire is coiled up again in step F and thensupplied to the second drawing step G, where the wire is redrawn to thedesired final dimensions, so that in step H, a coiled-up stapling wire hresults with the desired final diameter.

[0032] The method according to the invention is schematicallyillustrated in FIG. 2. A wire with good drawing properties having a lowcarbon content serves as the starting material 1, which, is firstcleaned for descaling in a cleaning device. This wire is supplied to afirst drawing step 2. The wire of the starting material 1 has a startingdiameter D₁. In the first drawing step 2, the wire of the startingmaterial 1 is drawn to a wire with an intermediate diameter D₂. For thispurpose, there is a first drawing device with multiple drawing dieshaving smaller and smaller diameters. While the starting diameter D₁ ofthe present wire is approximately 5.5 mm, after the first drawing step2, the wire has an intermediate diameter which typically varies between1.4 mm and 3.2 mm.

[0033] The wire is then coiled up in step 3 via an appropriate coilingdevice. In step 4, the wire is coated with an appropriate coatingdevice. In the present case, the wire is galvanized for surface finish.In principle, it is also possible to perform steps 2 and 4 in one line,without coiling in step 3. In the embodiment illustrated, the previouslycoiled wire is uncoiled via an appropriate coiling device and fedthrough an appropriate bath of the coating device. This wire is thenelectrolytically galvanized. In principle, hot galvanizing would also bepossible. Following this step, the galvanized wire is then coiled upagain in the step 5.

[0034] The galvanized wire with the intermediate diameter D₂ is thensupplied to a second drawing step 6, whose final product is the staplingwire 7 with the desired final diameter D₃. There is also a seconddrawing device with multiple drawing dies having diameters which becomesmaller and smaller. The stapling wire 7 is then coiled up again via anappropriate coiling device, which occurs in step 8.

[0035] The method schematically illustrated in FIG. 2 for the productionof stapling wire 7 is completely without heat treatment. However, astapling wire 7 is nonetheless produced which has excellent propertiesfor the intended purpose of stapling periodicals.

[0036] As already mentioned, steel with a low carbon content,particularly less than 0.06 weight-percent, is used as the startingmaterial 1 to ensure good drawing properties of the starting material 1.Thus, it is possible to draw the wire from a starting diameter D₁ of 5.5mm down to 0.7 mm or 0.2 mm without any heat treatment.

[0037] In the schematic illustration according to FIG. 2, step 4involves a galvanization bath. In principle, it is also possible toprovide other coating devices, or, in specific applications, to dispensewith the coating completely.

[0038] In the embodiment illustrated, the first drawing step 2 isperformed with the dry drawing process, while the second drawing step 6,due to the preceding surface finish, is performed with the wet drawingprocess. Dry drawing typically requires the use of an appropriate drylubricant. In this context, it is particularly favorable to provide,following the first drawing step 2, a step 9 (FIG. 3) for surfacecleaning of the wire for preferably complete removal of the drylubricant. An appropriate surface-cleaning device is provided for thispurpose. This step ensures that no dry lubricant residue remains on thewire when the coating is performed in step 4, so that the coatingadheres well on the staples produced from the wire. Otherwise, themethod illustrated in FIG. 3 corresponds to that in FIG. 2.

[0039] In FIG. 4, a stress-strain diagram is illustrated which, showsthe stress-strain properties of the stapling wire 7 formed by theprocess according to the invention and compares this curve to a staplingwire h produced according to the method of the prior art. It can be seenthat stapling wire 7 is harder, but definitely keeps its shape afterbending. Furthermore, stapling wire 7 can also be cut very well, so thatproblems in the stapling of periodicals or similar items are not aconcern. The values of the diagram indicated on the abscissa are onlyapplicable for one preferred embodiment of the wire produced accordingto the method according to the invention, but other value ranges arealso possible without any further measures.

[0040] Accordingly, while at least one embodiment of the presentinvention has been shown and described, it is to be understood that manychanges and modifications may be made thereunto without departing fromthe spirit and scope of the invention as defined in the appended claims.

What is claimed is:
 1. A method for the production of stapling wire inthe graphic industry comprising: providing a wire having a good startingmaterial with a low carbon content and having a starting diameter D1;drawing said wire from said starting diameter D1 to an intermediatediameter D2; and redrawing said wire from said intermediate diameter D2to said final diameter to produce said stapling wire wherein saidreduction in cross-sectional diameter of said wire is greater than 80%wherein said wire does not undergo any heat treatment during the drawingprocess from said starting diameter D1 to said final diameter D2.
 2. Themethod as in claim 1, wherein said step of providing a wire includesproviding a wire with a starting material with a carbon content of lessthan 0.6%.
 3. The method as in claim 1, wherein said step of redrawingthe wire draws the wire to a final diameter D(3) that is greater than99% reduced in diameter from said starting diameter D1.
 4. The method asin claim 1, wherein said step of providing a wire includes providing awire having a starting diameter of less than 10 mm.
 5. The method as inclaim 1, wherein said step of providing a wire includes providing a wirehaving a starting diameter of less than 5.5 mm.
 6. The method as inclaim 1, wherein said step of redrawing the wire redraws the wire toless than 0.7 mm.
 7. The method as in claim 1, further comprising thestep of applying a metallic coating to the wire as a surface finishbetween said first drawing step and said second drawing step.
 8. Themethod as in claim 7, wherein said wire is galvanized.
 9. The method asin claim 1, wherein said first drawing step is performed with a drydrawing process.
 10. The method as in claim 1, wherein said seconddrawing step is performed as a wet drawing process.
 11. The method as inclaim 1, wherein said second drawing step is performed as a dry drawingstep.
 12. The method as in claim 1, further comprising the step ofadding a dry lubricant to said wire before said first drawing step andcleaning said wire to remove said lubricant.
 13. The method according toclaim 1, further comprising the step of coiling the wire between saidfirst drawing step and said second drawing step.
 14. The method as inclaim 13, further comprising the step of applying a coating to the wireafter the first drawing step wherein said wire is coiled up after theapplication of said coating.
 15. The method as in claim 1, wherein saidsecond drawing step is performed without said wire having been coiledfollowing the first drawing step.